the bios is flashed, the newest sound driver is installed. but there is no sound and the microphone doesn't work too. (internal and external- both).. the computer see it, but no result..
one year ago, by installing the system i had the same problems. i tryed some older versions of the driver and it worked. now i lost this file and don't remember the version. and my "experiments" now are unsuccsessful..

with the graphic (NVIDIA GeForce Go 7900 GS) it's near the same- newest driver (7.15.11.7976 - nVIDIA ForceWare 179.76), but every 15-20 minutes the monitor is one "level" darker, so i go to the control panel and intensate the screen brightness manually.. (like in the first case the solution was an older driver).

your sound is not going to be so easy as tosh don't list a windows 7 driver leaving you with two options.

one is windows update and the other is the Compatibility Wizard loading the vista drivers.
i will see if i can find any drivers direct from microsoft for windows 7 but it may take me a while as i have to look at their database direct.
if i find anything at all i will upload it to site for you to try.

installed Conexant High Definition SmartAudio HD2 v.4.36.7.60 (11.04.2008)
it works. not good, but works.. after restarting the comp i have first to dlick (don't know in englisch, so a snapshot)):
after it the sound and microphone works.

ok been doing some reading at microsoft about your audio driver.
you have the newest driver installed however that one is listed as being a problem,
microsoft have a early version that you may wise to try
click here and download version 4.22 or 4.23 and try them on your laptop.

with your gfx card, go in to display options and open up the nvidia gefroce go powerplay.
tell it not to control the power output of the card and leave it at full power at all times, that might sort out your problem with the screen.

its normal for a geforce or ATI to start dimming the screen when your on battery, its just to help the battery last that much longer, but if you feel its a pain in the butt tell it not to do it.

i had it with vista and now i did a clean install of 7
nothing works for me.. will try out some other drivers. after sucsessfull installing will write an answer in this topic.. for this moment i don't have interesting news ((

go back in to your bios, look over the settings for the power options
you might have disabled it in windows, however you bios might still be the one
thats dimming that screen, its best to check that before you go crazy.

after installing 7.15.11.5666 and the new Value Added Package the gfx works fine.. (but there are not power saver controls in it - toshiba power saver has stopped on windows 7) - it was fine just after installing it- i didn't do anything else.

the tosh power saver program is supose too save you power.
IE dim your screen, i just wonder if it was that program that was giving you the problems if its not fully windows 7 compatible.

that a very early driver you have installed, however if its doing all the 3D work that you need thats good enough.
just keep a eye on windows update as it might pick up on the date of that driver and overwrite it with one from microsoft.

the gfx driver 7.15.11.7976 (27.03.2009) was instaled automatically after installing value added package.
the sound i let lay like it was by the installation: 6.1.7600.16385 (13.07.2009)

it was ok. just by the sound - by starting and shutdowning the system there was an click, or "cracking noise" everything else was ok.

after it i installed the (optional) update for the sound Conexant - Audio - Conexant High Definition Smartaudio HD2 (relased in april 2008), from the microsoft. that was the problem. for the sound, but for the gfx too (!)
the sound works like i wrote in post#5 and the display beguinns to be darken again.

after i restored the old sound driver and all problems disappeared.. (the "cracking noise" and darken display).

so, the driver combination, that is working for me is
sound: 6.1.7600.16385
gfx: 7.15.11.7976

so really you have the older windows vista drivers running on a windows 7 system.
which would make sense.
the updates from microsoft don't work so stop them from loading again by tell windows update not to show you.

the tosh HW setup utility is a old version as well.
keep a eye on tosh website for a update to that program as that is telling windows update about the hardware inside that machine.

if i was you before you go ahead with any updates that come out i would do a full and complete disk image of your working system, that way if things don't work out you can just load up your disk image and go back to a working state.

system restore is ok up to a point but sometimes things get over writen and its always best to have something in your desk that you know works.